Austroargiolestes isabellae is a species of Australian damselfly in the family Argiolestidae, commonly known as a Sydney flatwing. Endemic to the Sydney district, it inhabits streams and boggy areas.
It is a medium-sized to large, black and pale yellow damselfly, often with some pruinescence on adult bodies . Like other members of the Argiolestidae, it rests with its wings outspread.